Re: Deleting/moving multiple emails

hold control or shift as you select messages. drag and drop to a new folder.

as a general rule, you don't want to keep all of your mail forever - just the important stuff. (you would not believe the junk some people keep )
There is not real limitation, but too many slows it down when you change folders. I recommend keeping it somewhat small.
Archive methods vary - i cretae a new folder for each month and copy the mail i need kept to that folder. then close OE and move the file to my archive location. It's out of OE and safe.

Re: Deleting/moving multiple emails

I agree with MaryJ, about the stuff people save. If it is REALLY neaded to be saved, save it as a file ins a special folder on your hard drive. The use of the email folders to save every email one has received, sent and even drafted and not sent gets out of control. Bigger they get the slower ANY email program will run.